Apparatus for treating finely divided material



0. LELLEP March 19, 1935.

APPARATUS FOR TREATING FINELY DIVIDED MATERIAL Original Filed Oct. 18,1929 Patented Mar. 19, 1935 UNlTED \srATEs PATENT OFFICE.

. APPARATUS .FOR TREATING FINELY DIVIDED MATERIAL om Lellep, Duesseldorf, Germany, assignor to Lepol, InternationalePatentverwertnngs-Gesellschaft m. b. H., Berlin, Germany, and N. V.Solopol, Ingenieur-Bureau tot Exploitatie van het System erlandslolysius, s-Gravenhage, Neth- Original application October 18, 1929,Serial No.

Divided and this application August 23, 1934, Serial No. 741,176. InGermany December 15, 1927 8 Claims.

This invention relates to apparatus for the treatment of cement orsimilar pulverulent materials and more particularly to means foragglomerating cement raw material to facilitate the burning thereof. Itis the principal-object of the invention to provide a device of thischaracter which will effect the agglomeration of the material in nodulesof fairly uniform size and shape cement produced. It is an essentialfeature of my prior invention that the raw finely divided material isfirst agglomerated and thereafter pre-, burned by hot gases which areforced through the agglomerated material, the preburned material beingsubsequently delivered to a rotary kiln for the final step of burning.

By effecting the preburning of the raw material in the form ofagglomerates of the size of a.

pea or larger, excellent contact between the material and the hot gasesis ensured and the heat. receiving surfaces of the raw material arequite large as compared with the usual shaft kiln or rotary kilnpractice. Again, by treating the material in the agglomerated form, the'hot gases may be passed through the material without substantialobstruction to flow,"and the rate of flow of gas may be accordinglymaterially increased. It is obvious, however, that.if the agglomeratesare too small, the flow of gas therethrough will be retarded and if theyare too large, the interior of the nodules will not be subjected to thedirect action of the hot gases and the effectiveness of the process willbe accordingly decreased.

The importance of ensuring the production of nodules of substantiallyuniform size will therefore be readily appreciated, it being the primarypurpose of the present invention to effect an improvement in theoperation of the agglomerating apparatus shown in Figures 2 and 3 of myprior patent. This application is a division of my prior applicationSerial No. 400,705, filed October 18, 1929, the latter being directedmore particularly to an improvement of that part of the apparatusdisclosed in my prior Patent 1,775,313 relating to the prebuming of theagglomerated material.

Further objects and features of the invention will be apparent from'thefollowing description taken in connection with the accompanying drawing,in which:

Figure 1 is a longitudinal sectional view of apparatus for agglomeratingpulverulent material to which the invention has been applied;

Figure 2 is a transverse sectional view taken substantially on the line2-2 of Figure 1; Figure 3 is an end elevation of the agglomerating drumshown in Figures land 2;

Figure 4 is a partial longitudinal sectional view illustrating aslightly modified form of the in-.

vention Figure 5 is a transverse sectional viewon the line 5-5 of Figure4;

Figure 6 is a partial-longitudinal sectional view illustrating a furthermodification of the construction; and

Figure 7 is a transverse sectional view on the line7--7 of Figure 6.

In order to facilitate an understanding of the invention, specificlanguage is used in describing the several embodiments thereofillustrated in the drawing. It will nevertheless be understood that nolimitation of the scope offtheyinvention 2s is thereby intended and thatvarious modifications and alterations are contemplated such as wouldoccur to one skilled in the art to which the invention relates. Forinstance, while the in-' vention is particularly applicable to thetreatment of cement raw material and finds its principal use inconnection with apparatus such as described in my, prior Patent1,775,313,. it will be readily appreciated that the invention is ingeneral applicable to the agglomeration of powdered material wherever'itis desired to improve the quality and uniformity of size of theresulting agglomerates. I

Referring now more particularly to the drawing, it will be observed thatFigures 1 and 2" illustrate apparatus generally similar to that shown inmy prior Patent 1,775,313, this apparatus including as its principalelement a drum 10 which is preferably generally cylindrical in shape andwhich may be supported for rotation, for instance by rollers 11 engagingwith annular races 13 surrounding the drum, the rollers being mounted ona suitable stationary support 14. The drum may be rotated in anyconvenient manner, for instance by means of a source of motive powerassociated with one or more of therollers 11 which serve to support thedrum.

. Means are provided for introducing the material to be treated, forinstance cement raw matehopper 16 into which the material may bedeposited is provided with a conduit 1'1 in communication with the lowerend thereof, this conduit extending within the drum and through theopening at the inlet end of the drum, the latter being defined by theinwardly directed annular wall 18. A rotatable conveyor worm 20 withinthe conduit 17 may be employed to feed the material at a uniform ratefrom the hopper 16 to the drum 10 in the conventional manner.

A liquid supply pipe 23 extends within and is disposed generallylongitudinally of. the drum 10 throughout the entire length thereof,this pipe being provided with a valve 24 for controlling the flow ofliquid therein and being apertured at spaced intervals along a portionor over the whole length thereof, the dimension of the apertures and thepressure of the liquid supplied through the pipe 23 being preferably sorelated thzf, the liquid will fall in the form of drops or in a showeron the material within the drum. It is found that with this constructionif the material to be treated is agitated or kept in motionby=reasonably rapid rotation of the drum while the liquid is being thussupplied, each drop of liquid will form the nucleus of an agglomerate ornodule of the material which gradually builds up to the required size.

It will be understood that the size of these nodules is dependent tosome extent upon the size of the drops of water or other liquidintroduced, which is in turn controlled by the size of the apertures orby control of the pressure under which the water is supplied. As ageneral rule, in the treatment of cement raw material, it is found-thatapertures of .7 mm. diameter at a water pressure of .06 mm. will operatesatisfactorily. Under.these conditions a thin, substantially continuousjet of water flows from each aperture, this jet separating as it fallsinto drops which follow in rapid succession, the formation of the dropsbeing effected at a distanceof about 10 cm.-from the pipe 23.

In addition to the upward and downwar movement of the material along theperipheral walls of the drum, the material also moves steadily axiallyof the drum from the inlet toward the discharge end of the latter. Thisaxial motion may be ensured either by slightly inclining the drum at aratio of about 1: 100, or by the provision of conventional means withinthe drum for effecting positive displacement of the material. It isfound that with cement raw material the quantity of water preferred isapproximately 10% to 12% of the amount of material undergoing treatment,this percentage being suflicient to t ansform practically the entirequantity of mat rial into agglomerates or nodules. At the outset theseagglomerates are of irregular form and of weak structure, and relativelyfragile. The continuous friction, however, developed between thenodules' and between the drum walls and the nodules soon effects arounding of the nodules which eventually assume substantially sphericalshape, the strength thereof being gradually increased. The size of thesenodules may varyfrom a' diameter of several millimeters to about 20 mm.and more. The peripheral velocity of the drum may vary to a considerableextent butshould not exceed that velocity at which the raw material isprevented by the action of centrifugal force from falling awayfrom thewalls of the drum. In general the torque required for the rotation ofthe drum is about equal to the driving force necessary for a tube mill.Thus if 0.5 kilowatt hours are employed to rotate the drum in thetreatment of each barrel(170 kg.) of cement, the nodules will besufliciently hard so that the greater portion thereof will not breakwhen freely falling from a height of 2 meters.

It is of course possible to vary the agglomerating process to aconsiderable extent to modify the characteristics of the finishedmaterial. If it is desired, for instance, to produce agglomerates of aspecial strength, the raw material introduced into the drum may besaturated to a greater extent by increasing the fiow of water throughthe pipe 23, additional raw material being introduced through a separateconveyor at a point near the middle of the drum as measured axially;This conveyor may be similar to that shown in' Figure 1 for introducingthe main portion of the ma- 7 terial at the inlet end of the drum, theconveyor conduit being extended within the drum to the desired point. Bysuch an arrangement the excessive moisture of the material may bereduced to say 10% of the amount of raw material being treated.Variation in the strength and size of the nodules may also be effectedby alteration of the length over which the supply pipe 23 is perforated.Thus as illustrated more particularly in the drawing, the drops of watermay be caused to fall only in about the first half of the length of thedrum. In order to avoid adhesion of the material to the walls of thedrum, a stationary scraping member 26 may be provided, this member beingsupported on suitable standards 27 and extending longitudinally throughthe drum 10, the toothed portion 28 of this member engaging the drumwalls to remove the material therefrom.

When cement raw material is treated, it is of course advisable tomaintain the water content at a reasonably low value in order to effectsavingof the fuel required to burn the material. However, it has beenfound diflicult to (ensure satisfactory agglomeration of the material ifthe quantity of water employed is too small. Practice has shown thatsatisfactory results may be obtained with a water content of an amountapproximately 8% to 16% of the amount of the dry pulverized material.

In order to avoid the formation during the process of agglomeration oflumps of material of irregular size, pins 30 may be provided on theinterior surface of the drum, projecting radially inward therefrom andpassing through the material as the drum is rotated and between theteeth of the member 26. These pins ensure continuous agitation of thematerial and serve to loosen the same and prevent the formation oflumps. In lieu of the pins 30, or in addition thereto, prongs or-bladessuch as shown at 31 and 32 may be employed.

At or near the discharge end of the drum 10 an I annular member or stowring 35 is provided, this member preferably extending radially inwardfrom the peripheral wall of the drum and serving to impede to someextent the discharge of material from the drum so that the completion;

of the process of agglomeration may-be ensureii/ It will be observedthat the member 35 affords a generally circular opening 36 atthedischarge end of the drum through which the agglomerated material maypass, the discharged material falling into a hopper 38 located beneaththe drum on which the material is delivered to a conveyor, preferably ofthe type shown in my prior Patent 1,775,313, where it is preburned bythe hot waste kiln gases.

It is found that while the employment of a stow ring or the equivalentthereof is desirable,

the largeragglomerates, which tend to/collect adjacent the peripheralwall of the drum, areretained within the drum for a longer time than isThus the member 35 may be provided with an opening 40 therein of limitedcircumferential extent and disposed in contiguous relation to theperipheral wall of the drum. As the drum rotates, this opening willperiodically pass across the material contained in the lower portion ofthe drum and permit the discharge of a limited quan tity of the largernodules.

, In the construction shown in Figures 4 and 5 a slightly modifiedarrangement is disclosed, the annular member 42 which defines thedischarge opening 4lat the end of the drum being sub stantinallycontinuous, an opening 43 being provided directly in the peripheralwallof the drum adjacent the discharge end of the latter so that thelarger nodules may be delivered through this opening.

Figures 6 and '7 "illustrate a modification of the arrangement shown inFigures 4 and 5, th opening 43 in the peripheral wall of the drumcommunicating with 'a discharge spout 45 which may lie in a generallycircumferential direction and overlie the opening'43 so that thequantity of the larger nodules discharged at each rotation of the drummay be more accurately controlled. It will be understood that in all ofthese constructions both the smaller nodules which move through thegenerally circular opening nearer the axis of the drum and the largernodules which are discharged through the smaller opening adjacent theperiphery of the drum will fall within the same hopper 38 and passtherefrom to devices for effecting further treatment of by varying therelative sizes of the two discharge openings, the duration of the step,of agglomeration as applied to each nodule may be maintainedsubstantially constant, with the result that the strength, shape, andsize of the individual nodules is remarkably uniform and a decidedimprovement'in the treatment of cement raw material in accordance withthe teachings of my prior Patent 1,775,313 can be efiected.

Having thus described the invention, what is claimed as new and desiredto besecured 'byLet ters Patent is:

1. In apparatus for agglomerating powdered material, the combinationwith a container, of means for introducing the powdered material intothe container, means forv sprinkling liquid uni.-

formly upon the powdered material within the containe1;,.and' means forshifting the material during the sprinklingoperation to distribute theliuid throughout the entire mass of the material, said containerbeinggenerally cylindrical and having an opening spaced from theperipheral portion thereof for the discharge'of smaller agglomerates andan opening contiguous to the peripheral portion thereof for largeragglomerates. v

2. In apparatus for agglomerating powdered material, the combinationwith a container, of

means for introducing the powdered material into the container, means,for sprinkling liquid uniformly upon the powdered material within thecontainer, said container being generally cylindrical and having anopening spaced from the peripheral portion-thereof for the discharge ofsmaller agglomerates and an opening contiguous to the peripheral.portion thereof for larger agglomerates, and means for rotating thecontainer about the axis thereof.

3. In apparatus for agglomerating powdered material, the combinationwith a container, of means for introducing the powdered material intothe container, means for sprinkling liquid uniformly upon the powderedmaterial within the container, said container being generallycylindrical, having a material inlet end,'and having an opening spacedfrom the peripheral portion thereof for the discharge of smalleragglomerates and an opening contiguous to the peripheral portion thereoffor larger agglomerates, and means for rotating the container about theaxis thereof.

.4. In apparatus for agglomerating powderedthe drum for distributingliquid in the form ofdrops on the material therein, and means forrotating the drum whereby each drop of liquid forms a nucleus whichbuilds up to a nodule of appreciable size by agglomeration, said drumbeing generally cylindrical and having anopening spaced from theperipheral portion thereof for the discharge of smaller agglomerates andan opening contiguous to theperipheral portion thereof for largeragglomerates.

5. In apparatus for agglomerating powdered material, the combinationwith a drum for receiving the material, of means extending within thedrum for distributing liquid in the form of drops on .the materialtherein, and means for rotating the drum whereby each drop of liquidforms a nucleus which builds up to a nodule of appreciable size byagglomeration, said drum being provided adjacent one end with an annularmember extending radially inward from the periphery of the drum toprovide an opening for the discharge of smaller nodules, said memberhaving an opening therein adjacent the drum periphery and of limitedcircumferential extent for the discharge of large nodules.

6. In apparatus for 'agglomerating powdered material, the combinationwith a drum for receiving the material, of means extending within thedrum for distributing liquid in the form of drops on the materaltherein, and means 1'01- rotating the drum whereby each drop of liquidforms a nucleus whichbuilds up to a nodule of appreciable size byagglomeration, said drum being provided adjacent oneend with an annularmember extending radially inward from the periphery of the drum toprovide an opening for the discharge of smaller nodules, said drumhaving an opening in the periphery thereof adjacent said member oflimited circumferential extent for the discharge of larger nodules.

7. In apparatus for agglomerating powdered material, the combinationwith a drum for receiving the material, of means extending within thedrum for distributing liquid in the form of drops on the materialtherein, and means for rotating the drum whereby each drop .of liquidforms a nuclueus which builds up to a nodule of appreciable size byagglomeration, said drum being provided adjacent one end with an annular-member extending radially inward from the periphery of the drum toprovide an opening for the discharge of smaller nodules, said drumhaving an opening in the periphery thereof adjacent said member oflimited circumferential extent for the discharge of larger nodules, anda dscharge spout associated with said last named opening.

8. In apparatus for agglomerating powdered material, the combinationwith a drum for receiving the material, of means extending within thedrum for distributing liquid in the form of drops on the materialtherein, and means for rotating the drum whereby each drop of liquidforms a nucleus which builds up to a nodule of appreciable size byagglomeration, said drum being provided adjacent one end with an annularmember extending radially inward trom the opening, saiddischar'ge spoutextending circumferentially with respect to the .drum .and about theassociated opening.

O'I'IO LELLEP.

